Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
  • C08J9/0061—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof characterized by the use of several polymeric components
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2375/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
  • C08J2375/04—Polyurethanes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2483/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen, or carbon only; Derivatives of such polymers
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S521/00—Synthetic resins or natural rubbers -- part of the class 520 series
  • Y10S521/904—Polyurethane cellular product having high resiliency or cold cure property

Definitions

• the invention relates to a process for the production of highly resilient, cold-curing polyurethane foams.
• foams formed from at least difunctional polyisocyanates, polyols with at least two hydroxyl groups per molecule of which at least 40% on the average are primary hydroxyl groups, the polyols having an equivalent weight per hydroxyl groups of 700 to 3,000, as well as catalysts, blowing agents, emulsifiers, stabilizers and, if necessary, other conventional additives.
• a polyisocyanate which is at least difunctional, for example, toluene diisocyanate or diphenylmethane diisocyanate is reacted with a polyol, which has at least two hydroxyl groups per molecule and which, on the average, has a high proportion of primary hydroxyl groups.
• a polyol which has at least two hydroxyl groups per molecule and which, on the average, has a high proportion of primary hydroxyl groups.
• Such polyols are synthesized, as a rule, by first of all adding propylene oxide to a starter alcohol and then adding ethylene oxide to this product in amounts, such that at least 40% of the hydroxyl groups, and preferably 70 to 90% of the hydroxyl groups, are present in the form of primary hydroxyl groups.
• the polyols Due to the high content of primary hydroxyl groups, the polyols have a high reactivity towards isocyanates. In contrast to conventional polyurethane foams, i.e., the so-called hot foams, a high crosslinking density is therefore achieved during foaming. This has the advantage that there is no need to supply external energy during curing and that the overall time required for curing the foams is reduced. It is, however, a disadvantage that the tendency to form closed-cell foams is increased and the processing latitude is restricted.
• processing latitude is understood to be the tolerance limits within which it is possible to deviate from a formulation without endangering the formation of stable and, at the same time, open-celled foams.
• Formulations on this basis do not produce inherently stable foams. Thus, unless stabilizers are added, the foams collapse once again after they have risen. The stabilizers required for these foams must therefore have a stabilizing action against relapse, as well as a cell regulating action and must ensure the formation of open-celled foams over as wide a range as possible.
• One group is formed by polysiloxane-polyoxyalkylene copolymers, in which the polysiloxane blocks have a molecular weight of about 150 to 2,500 and the polyoxyalkylene blocks a molecular weight of about 150 to 1,500.
• the products are free of hydroxyl groups.
• Such products and their use in polyurethane foaming are described in U.S. Pat. Nos. 3,741,917 and 4,031,044.
• the other group of stabilizers comprises polysiloxanes which are modified with organic groups.
• groups are the cyanoalkyl group (U.S. Pat. No. 3,952,038), the cyanoalkoxyalkyl group (German Auslegeschrift No. 2 402 690, the sulfolanyloxyalkyl group (U.S. Pat. No. 4,110,272), the morpholinoalkoxyalkyl group (U.S. Pat. No. 4,067,828) and the tertiary hydroxyalkyl group (U.S. Pat. No. 4,039,490).
• a disadvantage of the aforementioned and, in principle, usable stabilizers is their relatively narrow processing latitude. This forces the processor to adhere to very close tolerances in metering out the foaming components, which cannot always be done with the required reliability.
• the main task of the stabilizer is to exert an equalizing function over the changes which occur in practice. It must be possible to adjust foam formulations of different reactivity and stability to the desired stabilizing level by changing the concentration of the stabilizer. For this reason, the processing latitude of a stabilizer with respect to changes in the concentration is of great practical importance. Higher and lower concentrations of a good stabilizer must stabilize the foam, as well as produce foams of comparable cell openness and cell structures.
• the stabilizers of the present invention are polysiloxanepolyoxyalkylene block copolymers having the following characteristics:
• the polysiloxane block is linear or branched and contains an average of 4 to 25 silicon atoms, wherein the organic radicals linked to the silicon atoms are polyoxyalkylene or methyl radicals and up to 30% of the methyl radicals can be replaced by substituted alkyl radicals with 1 to 4 carbon atoms and/or phenyl radicals;
• the polyoxyalkylene portion consists of at least two polyoxyalkylene blocks, A 1 and A 2 , which are formed from oxyethylene and oxypropylene units, wherein block A 1 is formed from 45 to 100 mole percent of oxyethylene units and 55 to 0 mole percent of oxypropylene units and block A 2 is formed from 0 to 50 mole percent of oxyethylene units and 100 to 50 mole percent of oxypropylene units, the molecular weight of the polyoxyalkylene blocks A 1 and A 2 in each case being 150 to 1,200 and the molar ratio of blocks A 1 :A 2 falling in the range of 20:80 to 80:20; and
• the polysiloxane block is linked to the polyoxyalkylene blocks by SiOC or SiC bridges, 1.5 to 10 polyoxyalkylene blocks being linked to each polysiloxane block on the average.
• polysiloxane-polyoxyalkylene block copolymers in which the polyoxyalkylene radicals are either exclusively terminal or exclusively lateral.
• the polyoxyalkylene blocks, A 1 and A 2 can be linked by SiC or SiOC groups to the polysiloxane blocks and consist predominantly of oxyethylene and oxypropylene units.
• R' is a hydrogen radical, an alkyl radical with 1 to 4 carbon atoms, a carboxyl radical or an alkylaryl radical.
• the inventive polysiloxane-polyoxyalkylene block copolymers can be synthesized by known procedures.
• the SiOC-linked copolymers can be formed, for example, by reacting polysiloxanes having terminal functional groups X, such as, halogen, sulfate or alkyl sulfonate, with polyoxyalkylene polymers having terminal hydroxyl groups in the presence of an acid acceptor, such as, for example, ammonia or tertiary amines.
• the SiC-linked copolymers are formed by reacting polysiloxanes, having terminal SiH groups and/or such groups in the polysiloxane chain, with polyoxyalkylenes having a terminal C ⁇ C double bond.
• Platinum catalysts in particular such as, for example, H 2 PtCl 6 O ⁇ 6H 2 O or cis-[Pt(NH 3 ) 2 Cl 2 ] are suitable for accelerating this addition reaction.
• block copolymers which are to be used in the inventive process would have the desired combination of properties.
• the desired improvements could not be achieved by varying the ethylene oxide/propylene oxide ratio in block copolymers, which have a homogeneous polyoxyalkylene portion nor by mixing block copolymers, each of which is uniform and, on the one hand, has the structure of blocks A 1 and, on the other, the composition of blocks A 2 .
• the linking of two polyoxyalkylene blocks of different structure to one polysiloxane segment therefore surprisingly results in a clear improvement relative to the known stabilizers of the state of the art.
• the organopolysiloxanes which are to be used in the inventive process, may optionally be combined with alkyl or alkylarylpolysiloxanes of relatively short chain length.
• Preferred examples of polysiloxanes of this type are those which have defined chain lengths with 4 to 15 silicon atoms.
• the inventive organopolysiloxanes can be used in admixture with nonionic organic emulsifiers, such as, for example, ethoxylated alkylphenols or fatty alcohol ethoxylates.
• Reaction components or additives which are known for and customarily used in the manufacture of highly resilient polyurethane foams, can be employed for the inventive process.
• difunctional polyisocyanates the isomers of toluene diisocyanate, the isomers of diphenylmethane diisocyanate or oligomeric polyphenylmethylene isocyanates can be used.
• the polyols have at least 2, and especially 2 to 8, hydroxyl groups per molecule of which, on the average, at least 40% and preferably 70 to 90%, are primary hydroxyl groups.
• the molecular weight per hydroxyl group (equivalent weight) is 700 to 3,000.
• the polyols may be built up exclusively of oxyethylene and oxypropylene units. Up to 30 weight percent of other polymeric components may be chemically bound or physically dispersed in the polyols.
• Such other polymeric components are, for example, polymers of styrene or acrylonitrile or copolymers thereof, as well as, for example, polymeric organic urea derivatives.
• the conventional catalysts such as, for example, organic salts of tin and tertiary amines are used.
• suitable blowing agents for this purpose are the chlorofluorohydrocarbons, which are known for this purpose.
• Further additives are flameproofing agents, such as, for example, chloroalkylphosphoric esters, as well as inert fillers and coloring pigments.
• polysiloxane-polyether copolymers which are to be used in the inventive process, are synthesized by methods, the principles of which are known.
• the procedures described in Examples 1 to 10 and especially 1 to 5 are examples of the synthesis of these products.
• a polyether A obtained by the addition reaction of 20 weight percent ethylene oxide and 80 weight percent propylene oxide with butylene glycol to a molecular weight of 51
• a polyether B obtained by the addition reaction of 60 weight percent of ethylene oxide and 40 weight
• Polyether C was obtained by the addition reaction of ethylene and propylene oxides with butylene glycol and contained 60 weight percent of propylene oxide. The molecular weight was 520. Consequently, the composition of polyether C corresponded to the average composition of the polyether mixture of polyethers A and B which was used in Example 1.
• the further examples show the reaction of SiH-containing siloxanes with allyl group-containing polyethers to form SiC-linked polysiloxane-polyoxyalkylene block copolymers.
• Polyether F was obtained by the addition reaction of ethylene and propylene oxides with allyl alcohol and contained 60 weight percent of propylene oxide. The iodine number was 46. The composition of polyether F therefore corresponded to the average composition of the polyether mixture of polyethers D and E which was used in Example 5.
• polysiloxane of the following average composition:
• polyether J The ethylene oxide/propylene oxide content of polyether J corresponds to that of the mixture of polyethers G and H used in Example 9.
• the components listed in formulations 1 or 2 below were weighed into a 2 l beaker and mixed for 60 seconds at 500 rpm with a propeller stirrer. Appropriate amounts of isocyanate were then added and the mixture was stirred for a further 7 seconds at 2,000 rpm.
• the reaction mixture was then added to an aluminum mold with the dimensions of 40 cm ⁇ 40 cm ⁇ 10 cm, which had been preheated to 50° C. and treated with a release agent. The molding time for both formulations was 8 minutes.
• the molded part was carefully taken from the mold for the determination of the impression force. Immediately afterwards, the indentation hardness was measured at 50% compression on that part of the foam which had not been pressed against.
• the round die used for this purpose had an area of 300 cm 2 . After the pressure was released, the closed cells present in the foamed part were opened up completely by extensive fulling. The indentation hardness at 50% compression was then measured once again. The difference between the two values was taken to be a measure of the impression force.
• the experiments were carried out on a 2-component Admiral low pressure machine.
• the polyol output was 10 kg/min.
• the foaming process took place in a box with the dimensions of 100 cm ⁇ 60 cm ⁇ 60 cm which was open at the top.
• the intensity of the blowing off was evaluated in the block foams in order to assess the effect of various stabilizers at different concentrations.
• the impression force, the porosity of the foamed materials and their resilience after impression were measured.
• the number of cells per cm of block foam was counted and the uniformity of the cell structure was evaluated. The measurements were carried out as follows:
• foaming was carried out in a box with the dimensions of 25 cm ⁇ 25 cm ⁇ 25 cm, which was open at the top. After a 2-day storage in a normal atmosphere, the top of the packet was cut off at a height of 20 cm. The indentation compression hardness was measured on the untouched as well as on the thoroughly fulled foam. The difference between the forces determined in N is the force which is required to impress the cells. A square die with an area of 100 cm 2 was used to measure the indentation forces.
• polysiloxane-polyoxyalkylene block copolymers which are to be used inventively, were checked in the following formulations for highly resilient polyurethane molded foams.
• Desmophen®3973 is a polyol of the Bayer AG Company which is built up exclusively from propylene and ethylene oxides and has more than 70% primary hydroxyl groups and an average molecular weight of 6,000.
• Desmophen®3119 is a polyol of the Bayer AG Company, which contains polymeric urea segments and has 70-80% primary hydroxyl groups and an average molecular weight of 6,000.
• TDI 80 is a mixture of the 2,4 and 2,6 isomers of toluene diisocyanate in the ratio of 80:20.
• the molded foams of this formulation have a relative density of approximately 34 kg/cm 3 .
• Voranol®CP 4711 is a polyol of the Dow Chemical Company which is built up exclusively from propylene and ethylene oxides and has approximately 70% primary hydroxyl groups and an average molecular weight of 4,800.
• Niax®Polyol 34-28 is a polyol of the Union Carbide Company which contains portions of a polymeric acrylonitrile/styrene and has predominantly primary hydroxyl groups and a hydroxyl number of 28.
• the molded foams formed with this formulation have a relative density of approximately 29 kg/m 3 .
• (C) 10 weight percent of a polysiloxane-polyoxyalkylene block copolymer, mixed with 86 weight percent of the same polyether as in (A) and 4 weight percent of a polydimethylsiloxane fraction of a chain length N 8 to 13.
• the block copolymers of Examples 1, 5 and 9 were used inventively as polysiloxane-polyoxyalkylene block copolymers in stabilizer mixtures A, B and C, the block copolymers of Examples 2, 3, and 4, as well as 6, 7, 8 and 10 were used for comparison.
• polysiloxane-polyoxyalkylene block copolymers which are to be used inventively, were furthermore tested in the following Formulations 3 and 4 for highly resilient polyurethane block foams.
• Desmophen®3900 is a polyol of the Bayer AG Company which is built up exclusively from propylene and ethylene oxides and has approximately 70% primary hydroxyl groups and an average molecular weight of 4,800.
• the foams of Formulation 3 had relative densities between 26 and 28 kg/cm 3 ; those of Formulation 4 had relative densities ranging from 42 to 45 kg/m 3 .
• polysiloxane-polyoxyalkylene block copolymers which are to be used inventively were checked in Formulations 3 and 4 using Stabilizer Mixture C.
• the inventive polysiloxane-polyoxyalkylene block copolymers give clearly lower impression forces and better porosities. In addition, they lead to better blowing off after rising, which is an additional measure of the completeness of cell opening. With all products, the cell structure was adequately uniform.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Polyurethanes Or Polyureas (AREA)
• Silicon Polymers (AREA)

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• 1982
  • 1982-09-17 DE DE3234462A patent/DE3234462C1/de not_active Expired
• 1983
  • 1983-09-03 DE DE8383108693T patent/DE3372488D1/de not_active Expired
  • 1983-09-03 EP EP83108693A patent/EP0106101B1/de not_active Expired
  • 1983-09-15 US US06/532,579 patent/US4478957A/en not_active Expired - Lifetime

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